A broad upper trough digging across the western US and associated 60+ knot mid-level jet yielded gusty winds and low RH across a broad portion of the southwest US on Sunday. Not only did widespread critical fire weather conditions exist, but numerous areas of blowing dust developed during the day amidst winds gusting over 50 mph at the surface. GOES Water Vapor imagery with RAP analysis fields captures the evolution of the system on Sunday (Fig 1). Downward momentum transfer across the southwest can be visualized in the WV imagery as darkening/warming (drying). Further, the tightening pressure gradient is apparent in the RAP MSLP field. Both GOES-West Mesoscale sectors were positioned across the Southwest to capture the blowing dust and wildfire threat.
A broad view from GOES-East Geocolor and IR SWD imagery during the afternoon provides a nice overview of the event (Fig 2 and 3). Blowing dust developed across soCA, NV, AZ, NM, CO, and wTx, with impressive smoke plumes also coming out of New Mexico and Arizona. Quite a few NWS Dust Storm Warnings were issued across the Southwest during the day, highlighting locations where blowing dust was restricting visibility considerably. As has been noted in past posts, these warning polygons are typically issued and shaped with some combination of, depending on availability, surface obs, webcams, other visual, satellite imagery. Satellite imagery was utilized by NWS offices in the issuance of the Dust Storm Warnings, discussion of the forecast in Area Forecast Discussions, and on Social Media, by impacted NWS offices.
Focusing on early blowing dust in New Mexico, NWS Albuquerque noted in an AFD at 2059 UTC: “A prominent dust plume is already evident on RGB satellite imagery over San Juan county where a Dust Storm Warning has been issued, and subsequent statements will likely follow.” The Dust Storm Warning, issued earlier at 1826 UTC, mentions Satellite imagery as the source of the warning. The NWS ABQ Twitter account communicated the location of the hazard using GOES Dust RGB imagery. One-minute Geocolor (Fig 4) and Dust RGB (Fig 5) imagery capture the blowing dust and smoke plumes in detail.
Further West NWS Las Vegas issued numerous Dust Storm Warnings across their CWA, with one reading: “At 417 PM PDT, dust channel moving across Death Valley Road near Dumont Dunes continues to be impressive on satellite imagery and is likely producing less than a quarter mile visibility.” By later in the afternoon, while dust could be diagnosed in GOES-West visible imagery (such as Geocolor), the lack of forward scattering from this location during the afternoon toward GOES-West makes it more difficult, compared to from GOES-East (Fig 6).
Therefore, bringing in IR-based products, such as SWD, to enhance dust appearance in the imagery is recommended (Fig 7), and/or viewing the IR-based RGBs (Fig 8).
Additional mentions of satellite imagery in AFDs for dust detection during this event included:
From NWS Phoenix, AZ at 2132 UTC: “Meanwhile, further west across the Imperial Valley blowing dust has already been detected on visible satellite imagery and local web cams, and this threat will continue into this evening.”
From NWS Reno, NV at 2133 UTC: “For now, we will keep an eye on gusts of 60-70 mph with wind prone areas possibly gusting to 80+ mph. Driving along N-S oriented roads such as US 395 and US 95 will be difficult for high-profile vehicles through the afternoon. Blowing dust is visible on satellite imagery near Lovelock, and this is likely to persist throughout Monday.”
From NWS Pueblo, CO at 2315 UTC: “Satellite imagery depicts a narrow channel of dust extending from northwest New Mexico northeastward into south-central Colorado. While much of this dust in southern Colorado appears to be concentrated aloft, surface visibilities have been lowering across the San Luis Valley, and may continue to fall this evening as additional dust is transported into the region. As a result, a Blowing Dust Advisory has been issued for the San Luis Valley, in addition to the eastern San Juan Mountains — specifically applying to southern areas of the mountains close to the Colorado-New Mexico border.”
Additional examples of NWS offices communicating the blowing dust hazard using satellite imagery from NWS Grand Junction, CO (DEBRA Dust) and El Paso, TX (Geocolor) are shown below.
Bill Line, NESDIS and CIRA